Outcomes and potential impact of a virtual hands-on training program on MRI staging confidence and performance in rectal cancer.

OBJECTIVES: To explore the potential impact of a dedicated virtual training course on MRI staging confidence and performance in rectal cancer. METHODS: Forty-two radiologists completed a stepwise virtual training course on rectal cancer MRI staging composed of a pre-course (baseline) test with 7 test cases (5 staging, 2 restaging), a 1-day online workshop, 1 month of individual case readings (n = 70 cases with online feedback), a live online feedback session supervised by two expert faculty members, and a post-course test. The ESGAR structured reporting templates for (re)staging were used throughout the course. Results of the pre-course and post-course test were compared in terms of group interobserver agreement (Krippendorf's alpha), staging confidence (perceived staging difficulty), and diagnostic accuracy (using an expert reference standard). RESULTS: Though results were largely not statistically significant, the majority of staging variables showed a mild increase in diagnostic accuracy after the course, ranging between + 2% and + 17%. A similar trend was observed for IOA which improved for nearly all variables when comparing the pre- and post-course. There was a significant decrease in the perceived difficulty level (p = 0.03), indicating an improved diagnostic confidence after completion of the course. CONCLUSIONS: Though exploratory in nature, our study results suggest that use of a dedicated virtual training course and web platform has potential to enhance staging performance, confidence, and interobserver agreement to assess rectal cancer on MRI virtual training and could thus be a good alternative (or addition) to in-person training. CLINICAL RELEVANCE STATEMENT: Rectal cancer MRI reporting quality is highly dependent on radiologists' expertise, stressing the need for dedicated training/teaching. This study shows promising results for a virtual web-based training program, which could be a good alternative (or addition) to in-person training. KEY POINTS: • Rectal cancer MRI reporting quality is highly dependent on radiologists' expertise, stressing the need for dedicated training and teaching. • Using a dedicated virtual training course and web-based platform, encouraging first results were achieved to improve staging accuracy, diagnostic confidence, and interobserver agreement. • These exploratory results suggest that virtual training could thus be a good alternative (or addition) to in-person training.

Intra-individual qualitative and quantitative comparison of [68Ga]Ga-DOTATATE PET/CT and PET/MRI.

Background: Somatostatin receptor (SSTR) positron emission tomography (PET) is a cornerstone of neuroendocrine tumor (NET) management. Hybrid PET/magnetic resonance imaging (MRI) is now available for NET-imaging, next to PET/computed tomography (CT). Objectives: To determine whether CT or MRI is the best hybrid partner for [68Ga]Ga-DOTATATE PET. Design: Monocentric, prospective study. Methods: Patients received a same-day [68Ga]Ga-DOTATATE PET/CT and subsequent PET/MRI, for suspicion of NET, (re)staging or peptide receptor radionuclide therapy-selection. The union (PETunion) of malignant lesions detected on PETCT and PETMRI was the reference standard. Concordance of detection of malignant lesions in an organ was measured between PETunion and CT and PETunion and MRI. Seven bins were used to categorize the number of malignant lesions, containing following ordinal variables: 0, 1, 2-5, 6-10, 11-20, >20 countable and diffuse/uncountable. The difference in number of malignant lesions was obtained as the difference in bin level ('Δbin') between PETunion and CT and PETunion and MRI with a Δbin closer to zero implying a higher concordance rate. Results: Twenty-nine patients were included. Primary tumors included 17 gastroenteropancreatic-NETs, 1 colon neuroendocrine carcinoma, 7 lung-NETs and 2 meningiomas. Patient level concordance with PETunion was 96% for MRI and 67% for CT (p = 0.039). Organ level concordance with PETunion was 74% for MRI and 40% for CT (p < 0.0001). In bone, there was a higher concordance rate for MRI compared to CT, 92% and 33%, respectively (p = 0.016). Overall, a mean Δbin of 0.5 ± 1.1 for PETunion/MRI and 1.4 ± 1.2 for PETunion/CT (p < 0.0001) was noted. In liver, a mean Δbin of 0.0 ± 1.1 for PETunion/MRI and 1.7 ± 1.2 for PETunion/CT was observed (p = 0.0078). In bone, a mean Δbin closer to zero was observed for PETunion/MRI compared to PETunion/CT, 0.6 ± 1.4 and 2.0 ± 1.5, respectively (p = 0.0098). Conclusions: Compared to SSTR PET/CT, SSTR PET/MRI had a higher patient and organ level concordance for malignant tumoral involvement and number of malignant lesions, with a clear added value in bone and liver specifically.

Sense and nonsense of yT-staging on MRI after chemoradiotherapy in rectal cancer.

AIM: The aim of this work was to investigate the value of rectal cancer T-staging on MRI after chemoradiotherapy (ymrT-staging) in relation to the degree of fibrotic transformation of the tumour bed as assessed using the pathological tumour regression grade (pTRG) of Mandard as a standard of reference. METHOD: Twenty two radiologists, including five rectal MRI experts and 17 'nonexperts' (general/abdominal radiologists), evaluated the ymrT stage on the restaging MRIs of 90 rectal cancer patients after chemoradiotherapy. The ymrT stage was compared with the final ypT stage at histopathology; the percentages of correct staging (ymrT = ypT), understaging (ymrT < ypT) and overstaging (ymrT > ypT) were calculated and compared between patients with predominant tumour at histopathology (pTRG4-5) and patients with predominant fibrosis (pTRG1-3). Interobserver agreement (IOA) was computed using Krippendorff's alpha. RESULTS: Average ymrT/ypT stage concordance was 48% for the experts and 43% for the nonexperts; ymrT/ypT stage concordance was significantly higher in the pTRG4-5 subgroup (58% vs. 41% for the pTRG1-3 group; p = 0.01), with the best results for the MRI experts. Overstaging was the main source of error, especially in the pTRG1-3 subgroup (average overstaging rate 38%-44% vs. 13%-55% in the pTRG4-5 subgroup). IOA was higher for the expert versus nonexpert readers (α = 0.67 vs. α = 0.39). CONCLUSIONS: ymrT-staging is moderately accurate; accuracy is higher in poorly responding patients with predominant tumour but low in good responders with predominant fibrosis, resulting in significant overstaging. Radiologists should shift their focus from ymrT-staging to detecting gross residual (and progressive) disease, and identifying potential candidates for organ preservation who would benefit from further clinical and endoscopic evaluation to guide final treatment planning.

Predicting response to chemoradiotherapy in rectal cancer via visual morphologic assessment and staging on baseline MRI: a multicenter and multireader study.

PURPOSE: Pre-treatment knowledge of the anticipated response of rectal tumors to neoadjuvant chemoradiotherapy (CRT) could help to further optimize the treatment. Van Griethuysen et al. proposed a visual 5-point confidence score to predict the likelihood of response on baseline MRI. Aim was to evaluate this score in a multicenter and multireader study setting and compare it to two simplified (4-point and 2-point) adaptations in terms of diagnostic performance, interobserver agreement (IOA), and reader preference. METHODS: Twenty-two radiologists from 14 countries (5 MRI-experts,17 general/abdominal radiologists) retrospectively reviewed 90 baseline MRIs to estimate if patients would likely achieve a (near-)complete response (nCR); first using the 5-point score by van Griethuysen (1=highly unlikely to 5=highly likely to achieve nCR), second using a 4-point adaptation (with 1-point each for high-risk T-stage, obvious mesorectal fascia invasion, nodal involvement, and extramural vascular invasion), and third using a 2-point score (unlikely/likely to achieve nCR). Diagnostic performance was calculated using ROC curves and IOA using Krippendorf's alpha (α). RESULTS: Areas under the ROC curve to predict the likelihood of a nCR were similar for the three methods (0.71-0.74). IOA was higher for the 5- and 4-point scores (α=0.55 and 0.57 versus 0.46 for the 2-point score) with best results for the MRI-experts (α=0.64-0.65). Most readers (55%) favored the 4-point score. CONCLUSIONS: Visual morphologic assessment and staging methods can predict neoadjuvant treatment response with moderate-good performance. Compared to a previously published confidence-based scoring system, study readers preferred a simplified 4-point risk score based on high-risk T-stage, MRF involvement, nodal involvement, and EMVI.

Comparison of MRI response evaluation methods in rectal cancer: a multicentre and multireader validation study.

OBJECTIVES: To compare four previously published methods for rectal tumor response evaluation after chemoradiotherapy on MRI. METHODS: Twenty-two radiologists (5 rectal MRI experts, 17 general/abdominal radiologists) retrospectively reviewed the post-chemoradiotherapy MRIs of 90 patients, scanned at 10 centers (with non-standardized protocols). They applied four response methods; two based on T2W-MRI only (MRI tumor regression grade (mrTRG); split-scar sign), and two based on T2W-MRI+DWI (modified-mrTRG; DWI-patterns). Image quality was graded using a 0-6-point score (including slice thickness and in-plane resolution; sequence angulation; DWI b-values, signal-to-noise, and artefacts); scores < 4 were classified below average. Mixed model linear regression was used to calculate average sensitivity/specificity/accuracy to predict a complete response (versus residual tumor) and assess the impact of reader experience and image quality. Group interobserver agreement (IOA) was calculated using Krippendorff's alpha. Readers were asked to indicate their preferred scoring method(s). RESULTS: Average sensitivity/specificity/accuracy was 57%/64%/62% (mrTRG), 36%/79%/66% (split-scar), 40%/79%/67% (modified-mrTRG), and 37%/82%/68% (DWI-patterns); mrTRG showed higher sensitivity but lower specificity and accuracy (p < 0.001) compared to the other methods. IOA was lower for the split scar method (0.18 vs. 0.39-0.43). Higher reader experience had a significant positive effect on diagnostic performance and IOA (except for the split scar sign); below-average imaging quality had a significant negative effect on diagnostic performance. DWI pattern was selected as the preferred method by 73% of readers. CONCLUSIONS: Methods incorporating DWI showed the most favorable results when combining diagnostic performance, IOA, and reader preference. Reader experience and image quality clearly impacted diagnostic performance emphasizing the need for state-of-the-art imaging and dedicated radiologist training. KEY POINTS: • In a multireader study comparing 4 MRI methods for rectal tumor response evaluation, those incorporating DWI showed the best results when combining diagnostic performance, IOA, and reader preference. • The most preferred method (by 73% of readers) was the "DWI patterns" approach with an accuracy of 68%, high specificity of 82%, and group IOA of 0.43. • Reader experience level and MRI quality had an evident effect on diagnostic performance and IOA.

Early Whole-Body Diffusion-weighted MRI Helps Predict Long-term Outcome Following Peptide Receptor Radionuclide Therapy for Metastatic Neuroendocrine Tumors.

Purpose To evaluate the predictive value of 7-week apparent diffusion coefficient change from baseline (ADCratio7w) at whole-body diffusion-weighted MRI (WB-DWI MRI) after one peptide receptor radionuclide therapy (PRRT) cycle to predict outcome in patients with metastatic neuroendocrine tumor (mNET). Materials and Methods From April 2009 to May 2012, participants in a prospective clinical trial investigating yttrium 90-DOTA Phe1-Tyr3-octreotide (DOTATOC) treatment for mNET (EudraCT no. 2008-007965-22) underwent WB-DWI MRI and gallium 68 (68Ga)-DOTATOC PET/CT before and 7 weeks after one PRRT cycle. ADCratio7w response was compared with the 7-week Response Evaluation Criteria in Solid Tumors version 1.1 and 68Ga-DOTATOC PET/CT quantitative responses to predict overall survival (OS) and progression-free survival (PFS) with Cox regression analysis. Results Forty participants were analyzed (mean age, 60 years ± 11 [SD]; 21 men). Median PFS and OS were 10.5 months (range, 2-36 months) and 18 months (range, 3-81 months), respectively. Survival analysis showed significantly positive effects on PFS by age (hazard ratio [HR] = 0.96, P = .007), tumor grade (HR = 2.84, P = .006), Ki-67 index (HR = 1.05, P = .01), ADCratio7w of the least-responding lesion (ADCratio7w-least) (HR = 0.94, P < .001), and baseline mean standardized uptake values (SUVmean) (HR = 0.89, P = .02), with ADCratio7w-least and SUVmean remaining significant in multivariable analysis (P < .001, P = .02, respectively). There were significantly positive effects on OS by pretreatment lesion volume (HR = 1.004, P = .004), tumor grade (HR = 2.14, P = .04), Ki-67 index (HR = 1.05, P = .01), and ADCratio7w-least (HR = 0.97, P < .001), with pretreatment volume and ADCratio7w-least remaining significant at multivariable analysis (P = .005, P = .002, respectively). Conclusion The ADCratio7w after start of PRRT for mNET was an independent predictor of patient outcome. Keywords: MR-Diffusion-Weighted Imaging, Radionuclide Therapy, Whole-Body Imaging, Metastases, Tumor Response, Treatment Effects EudraCT no. 2008-007965-22 © RSNA, 2022.

The sigmoid take-off as a landmark to distinguish rectal from sigmoid tumours on MRI: Reproducibility, pitfalls and potential impact on treatment stratification.

PURPOSE: The sigmoid take-off (STO) was recently introduced as a preferred landmark, agreed upon by expert consensus recommendation, to discern rectal from sigmoid cancer on imaging. Aim of this study was to assess the reproducibility of the STO, explore its potential treatment impact and identify its main interpretation pitfalls. METHODS: Eleven international radiologists (with varying expertise) retrospectively assessed n = 155 patients with previously clinically staged upper rectal/rectosigmoid tumours and re-classified them using the STO as completely below (rectum), straddling the STO (rectosigmoid) or completely above (sigmoid), after which scores were dichotomized as rectum (below/straddling STO) and sigmoid (above STO), being the clinically most relevant distinction. A random subset of n = 48 was assessed likewise by 6 colorectal surgeons. . RESULTS: Interobserver agreement (IOA) for the 3-category score ranged from κ0.19-0.82 (radiologists) and κ0.32-0.72 (surgeons), with highest scores for the most experienced radiologists (κ0.69-0.76). Of the 155 cases, 44 (28%) were re-classified by ≥ 80% of radiologists as sigmoid cancers; 36 of these originally received neoadjuvant treatment which in retrospect might have been omitted if the STO had been applied. Main interpretation pitfalls were related to anatomical variations, borderline cases near the STO and angulation of axial imaging planes. CONCLUSIONS: Good agreement was reached for experienced radiologists. Despite considerable variation among less-expert readers, use of the STO could have changed treatment in ±1/4 of patients in our cohort. Identified interpretation pitfalls may serve as a basis for teaching and to further optimize MR protocols.

Transarterial Radioembolization Following Chemoembolization for Unresectable Hepatocellular Carcinoma: Response Based on Apparent Diffusion Coefficient Change is an Independent Predictor for Survival.

PURPOSE: To evaluate whether response based on contrast-enhanced magnetic resonance imaging (MRI) and apparent diffusion coefficient (ADC) change at diffusion-weighted MRI after transarterial radioembolization (TARE) can predict survival, in patients with prior transarterial chemoembolization with drug-eluting beads (DEB-TACE) for hepatocellular carcinoma (HCC). METHODS: We identified all patients who received DEB-TACE prior to TARE for HCC between 2007 and 2016. Response on MRI was determined by modified RECIST (mRECIST) and ADC change relative to pre-TARE imaging (ADCratio). Kaplan-Meier and log-rank tests were used to correlate the response/disease and treatment variables to overall survival. Multivariable Cox regression models were used to correct for confounders. RESULTS: A total of 29 consecutive patients were included. Univariable analysis showed that response determined by mRECIST was a nonsignificant predictor of survival (p = 0.057), and response determined by ADCratio was a significant predictor of survival (p = 0.011). Number of prior DEB-TACE procedures (p = 0.037), female gender (p < 0.001) and BCLC C (p = 0.03) were related to worse survival. The number of prior DEB-TACE procedure was significantly higher in non-responders determined by ADCratio (p = 0.028). Multivariable analyses showed that response based on ADCratio was an independent predictor of survival (p = 0.041). CONCLUSION: ADCratio following TARE is an independent predictor for survival in patients who previously underwent DEB-TACE for HCC.

Feasibility of whole-body diffusion-weighted MRI for detection of primary tumour, nodal and distant metastases in women with cancer during pregnancy: a pilot study.

OBJECTIVES: To evaluate the feasibility of whole-body diffusion-weighted MRI (WB-DWI/MRI) for detecting primary tumour, nodal and distant metastases in pregnant women with cancer. METHODS: Twenty pregnant patients underwent WB-DWI/MRI in additional to conventional imaging. Reproducibility of WB-DWI/MRI between two readers was evaluated using Cohen's κ statistics and accuracy was compared to conventional imaging for assessing primary tumour site, nodal and visceral metastases. RESULTS: Both WB-DWI/MRI readers showed good-very good agreement for lesion detection (primary lesions: κ=1; lymph nodes: κ=0.89; distant metastases: κ=0.61). Eight (40 %) patients were upstaged after WB-DWI/MRI. For nodal metastases, WB-DWI/MRI showed 100 % (95 % CI: 83.2-100) sensitivity for both readers with specificity of 99.4 % (96.9-100) and 100 % (80.5-100) for readers 1 and 2, respectively. For distant metastases, WB-DWI/MRI showed 66.7 % (9.4-99.2) and 100 % (29.2-100) sensitivity and specificity of 94.1 % (71.3-99.9) and 100 % (80.5-100) for readers 1 and 2, respectively. Conventional imaging showed sensitivity of 50 % (27.2-72.8) and 33.3 % (0.8-90.6); specificity of 100 % (98-100) and 100 % (80.5-100), for nodal and distant metastases respectively. CONCLUSIONS: WB-DWI/MRI is feasible for single-step non-invasive staging of cancer during pregnancy with additional value for conventional imaging procedures. KEY POINTS: • In our study, WB-DWI/MRI was more accurate than conventional imaging during pregnancy. • WB-DWI/MRI improves diagnostic assessment of patients with cancer during pregnancy. • Accurate imaging and oncologic staging improves treatment and outcome.

Safety and Efficacy of Transarterial Radioembolisation in Patients with Intermediate or Advanced Stage Hepatocellular Carcinoma Refractory to Chemoembolisation.

INTRODUCTION: Transarterial chemoembolisation (TACE) is the most widely used locoregional treatment for patients with an unresectable hepatocellular carcinoma (HCC). Transarterial radioembolisation (TARE) with yttrium-90 containing microspheres is an emerging interventional treatment that could be complementary or an alternative to TACE. AIM: To evaluate the safety and efficacy of TARE in patients with HCC who are refractory to TACE with drug-eluting beads (DEB-TACE). METHODS: We identified all patients who received TARE for HCC following one or more sessions of DEB-TACE in the period 2007-2016. Grade ≥3 adverse events were graded according to Common Terminology Criteria for Adverse events. Response on MRI was determined on MRI by modified RECIST. Overall survival was estimated using the Kaplan-Meier method and was determined from the first TACE and from the TARE procedure. RESULTS: A total of 30 patients were included. Patients had a mean of 1.7 TACE procedures (range 1-4) prior to TARE. Grade 3 adverse events following TARE included: fatigue (20%), bilirubin increase (10%), cholecystitis (3.3%) and a gastric ulcer (3.3%). Response on MRI was achieved in 36.7%. Three patients (10%) were downstaged within the Milan criteria and received liver transplantation. The median overall survival after first TACE was 32.3 months (17.2-42.1 95% CI). The median overall survival after TARE was 14.8 months (8.33-26.5 95% CI). CONCLUSION: TARE is safe and can be effective in patients with an intermediate or advanced stage HCC who are refractory to TACE. This treatment strategy has the potential to downstage to liver transplantation.

Absence of tumor invasion into pelvic structures in locally recurrent rectal cancer: prediction with preoperative MR imaging.

PURPOSE: To retrospectively assess the accuracy of preoperative magnetic resonance (MR) imaging for identification of tumor invasion into pelvic structures in patients with locally recurrent rectal cancer scheduled to undergo curative resection. MATERIALS AND METHODS: The institutional review board approved this study, and informed consent was waived because of the retrospective nature of the study. Preoperative MR images in 40 consecutive patients with locally recurrent rectal cancer scheduled to undergo curative treatment between October 2003 and November 2006 were analyzed retrospectively. Four observers with different levels of experience in reading pelvic MR images assessed tumor invasion into the following structures: bladder, uterus or seminal vesicles, vagina or prostate, left and right pelvic walls, and sacrum. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated, and a receiver operating characteristic curve was constructed. Surgical and/or histopathologic findings were used as the reference standard. Interobserver agreement was measured by using kappa statistics. RESULTS: Preoperative MR imaging was accurate for the prediction of tumor invasion into structures with negative predictive values of 93%-100% and areas under receiver operating characteristic curves of 0.79-1.00 for all structures and observers. Positive predictive values were 53%-100%. Disease was overstaged in 11 (observer 1), 22 (observer 2), 10 (observer 3), and nine (observer 4) structures and was understaged in nine (observer 3) and two (observer 4) structures. Assessment failures were mainly because of misinterpretation of diffuse fibrosis, especially at the pelvic side walls. Interobserver agreement ranged between 0.64 and 0.99 for experienced observers. CONCLUSION: Preoperative MR imaging is accurate for the prediction of absence of tumor invasion into pelvic structures. MR imaging may be useful as a preoperative road map for surgical procedure and may thus increase chances of complete resection. Interpretation of diffuse fibrosis remains difficult.

Locally advanced rectal cancer: MR imaging for restaging after neoadjuvant radiation therapy with concomitant chemotherapy. Part I. Are we able to predict tumor confined to the rectal wall?

PURPOSE: To retrospectively assess accuracy of magnetic resonance (MR) imaging after radiation therapy with concomitant chemotherapy for downsizing of the primary lesion to ypT0-2 tumor confined to rectal wall in locally advanced rectal cancer, with histopathologic findings as reference standard, and to evaluate additional value of volumetric analysis. MATERIALS AND METHODS: The institutional review board approved the study and waived informed consent. Sixty-seven patients met criteria of the study. T2-weighted MR images obtained before and after radiation therapy with concomitant chemotherapy were assessed for tumor stage by expert abdominal radiologist, colorectal surgeon, and general radiologist. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated; tumor volume was measured (compared with Mann-Whitney U test). Findings were correlated with histopathologic findings. RESULTS: Sixty-seven patients (38 men, 29 women; mean age, 63 years) who underwent radiation therapy with concomitant chemotherapy and surgery (all but one) were evaluated. The PPV for prediction of tumor confined to rectal wall (ypT0-2) was 91% (10 of 11), 86% (six of seven), and 88% (seven of eight) for expert abdominal radiologist, surgeon, and general radiologist, respectively. In 24 patients, sensitivity was 42% (10), 25% (six), and 29% (seven). ypT0-2 tumors had significantly smaller volumes than did ypT3-4 tumors before radiation therapy with concomitant chemotherapy (55 vs 92 cm(3), P = .038). Volume reduction rates were significantly higher in ypT0-2 than in ypT3-4 tumors (89% vs 61%, P < .001). If volume before radiation therapy with concomitant chemotherapy was 50 cm(3) or smaller and volume reduction rate was 75% or higher, excised tumor was always confined to rectal wall (ypT0-2). By using these criteria, 43% (six of 14) of cases with overstaging could have been predicted to be ypT0-2 tumors correctly. CONCLUSION: Downsizing to ypT0-2 tumors can be accurately predicted by combining morphologic tumor staging predictions with results from volumetric analyses. MR images obtained after radiation therapy with concomitant chemotherapy might be helpful in more individualized treatment planning.

Radicality of resection and survival after multimodality treatment is influenced by subsite of locally recurrent rectal cancer.

PURPOSE: To analyze results of multimodality treatment in relation to subsite of locally recurrent rectal cancer (LRRC). METHOD AND MATERIALS: A total of 170 patients with LRRC who underwent treatment between 1994 and 2008 were studied. The basic principle of multimodality treatment was preoperative (chemo)radiotherapy, intended radical surgery, and intraoperative radiotherapy. The subsites of LRRC were classified as presacral, posterolateral, (antero)lateral, anterior, anastomotic, or perineal. Subsites were related to radicality of the resection, local re-recurrence rate, distant metastasis rate, and cancer-specific survival. RESULTS: R0 resections were achieved in 54% of the patients, and 5-year cancer-specific survival was 40.5%. The worst outcomes were seen in presacral LRRC, with only 28% complete resections and 19% 5-year survival (p = 0.03 vs. other subsites). Anastomotic LRRC resulted in the most favorable outcomes, with 77% R0 resections and 60% 5-year survival (p = 0.04). Generally, if a complete resection was achieved, survival improved, except in posterolateral LRRC. Local re-recurrence and metastasis rate were lowest in anastomotic LRRC. CONCLUSIONS: Classification of the subsite of LRRC is a predictor of potentially resectable and consequently curable disease. Treatment of posterior LRRC imposes poor results, whereas anastomotic LRRC location shows superior results.

Pre-operative staging with positron emission tomography in patients with pelvic recurrence of rectal cancer.

BACKGROUND/AIM: The treatment of pelvic recurrences of rectal cancer is primarily surgical. The substantial morbidity and mortality of such resections warrant stringent patient selection. Recent literature reports PET to be of additional value to CT for the detection of metastases in colorectal cancer patients. We studied the clinical impact of PET in pelvic rectal cancer recurrence. METHODS: PET findings in 37 pelvic recurrences of rectal cancer were evaluated retrospectively. Comparison was made to CT and MRI findings. It was analyzed whether PET had been decisive in clinical decision making or could have been so. RESULTS: Thirty-two patients had 37 rectal cancer recurrences. PET differed from conventional imaging in 13 cases (35%): seven PET scans showed lesions that were not seen with CT or MRI. PET scans were negative in six lesions detected by CT or MRI. PET alone changed management in five recurrences (14%). Four PET scans were false-positive; this had clinical implications in 2 patients. CONCLUSION: In a selected population with pelvic rectal cancer recurrences, PET had additional value to conventional imaging, mainly in detecting lymph node metastases. PET findings thus had a significant impact on selection of patients for curative surgery.

Radical resection after IORT-containing multimodality treatment is the most important determinant for outcome in patients treated for locally recurrent rectal cancer.

BACKGROUND: The optimal treatment for locally recurrent rectal cancer (LRRC) is still a matter of debate. This study assessed the outcome of LRRC patients treated with multimodality treatment, consisting of neoadjuvant radio (chemo-) therapy, extended resection, and intraoperative radiotherapy. METHODS: One hundred and forty-seven consecutive patients with LRRC who underwent treatment between 1994 and 2006 were studied. The prognostic values of patient-, tumor- and treatment-related characteristics were tested with uni- and multivariate analysis. RESULTS: Median overall survival was 28 months (range 0-146 months). Five-year overall, disease-free, and metastasis-free survival and local control (OS, DFS, MFS, and LC respectively) were 31.5%, 34.1%, 49.5% and 54.1% respectively. Radical resection (R0) was obtained in 84 patients (57.2%), microscopically irradical resection (R1) in 34 patients (23.1%), and macroscopically irradical resection (R2) in 29 patients (19.7%). For patients with a radical resection median OS was 59 months and the 5-year OS, DFS, MFS, and LC were 48.4%, 52.3%, 65.5% and 68.9%, respectively. Radical resection was significantly correlated with improved OS, DFS, and LC (P < 0.001). Patients who received re-irradiation or full-course radiotherapy survived significantly longer (P = 0.043) and longer without local recurrence (P = 0.038) or metastasis (P < 0.001) compared to patients who were not re-irradiated. CONCLUSIONS: Radical resection is the most significant predictor of improved survival in patients with LRRC. Neoadjuvant radio (chemo-) therapy is the best option in order to realize a radical resection. Re-irradiation is feasible in patients who already received irradiation as part of the primary rectal cancer treatment.

Mesorectal fascia invasion after neoadjuvant chemotherapy and radiation therapy for locally advanced rectal cancer: accuracy of MR imaging for prediction.

PURPOSE: To retrospectively assess sensitivity and specificity of magnetic resonance (MR) imaging after chemotherapy and radiation therapy for predicting tumor invasion of the mesorectal fascia (MRF) in locally advanced primary rectal cancer, by using results of histologic examination and surgery as the reference standard, and to determine morphologic MR imaging criteria for MRF invasion. MATERIALS AND METHODS: The Ethical Committee of University Hospital Maastricht approved this study and waived informed consent. Two observers independently scored postchemoradiation MR images in 64 patients with rectal cancer (38 male [mean age, 60 years] and 26 female [mean age, 64 years] patients) for MRF tumor invasion with a confidence level scoring system defined by subjective criteria. In a subsequent consensus reading session, morphologic MR criteria for invasion were defined by comparing morphologic changes with histologic findings. These criteria were evaluated and compared with the subjective criteria by comparing areas under the receiver operating characteristic curves (AUCs). RESULTS: AUCs of postchemoradiation MR imaging for predicting MRF tumor invasion were 0.81 and 0.82 for observers 1 and 2, respectively. The following four types of morphologic tissue patterns at MR imaging were associated with whether or not MRF invasion was present at histologic examination: (a) development of fat pad larger than 2 mm (seen in no quadrants with and in four quadrants without invasion), (b) development or persistence of spiculations (seen in no quadrants with and in 22 quadrants without invasion), (c) development of diffuse hypointense "fibrotic" tissue (seen in 21 quadrants with and in 32 quadrants without invasion), and (d) persistence of diffuse iso- or hyperintense tissue (seen in 19 quadrants with and in two quadrants without invasion). AUC of postchemoradiation MR imaging for predicting MRF invasion on the basis of morphologic criteria was 0.80. There was no significant difference between the performance of subjective and morphologic criteria (P = .73-.76). CONCLUSION: Postchemoradiation MR imaging findings have moderate accuracy for predicting tumor invasion of the MRF related to the limitation in differentiating between diffuse "fibrotic" tissue with and that without small tumor foci. Specific other types of morphologic patterns at MR imaging can highly predict a tumor-free or invaded MRF.